PREDICTING PROGRESSION FROM MILD COGNITIVE IMPAIRMENT (MCI) TO ALZHEIMER’S DISEASE USING PERFUSION BRAIN SPECT IMAGING ANALYSIS OF THE INITIAL HOSPITAL VISIT

Abstract

Mild Cognitive Impairment (MCI) has been proposed as a transitional stage between the cognitive changes of normal aging and dementia. 10 to 15% of MCI patients progress to Alzheimer's disease (AD) within one year. The aim of this study was to investigate whether perfusion brain SPECT imaging at the initial hospital visit could predict progression from MCI to AD. The SPECT device used in this study was Infina Hawkeye 4, General Electronics, with rotating two-headed gamma camera with a fan beam collimator (64x64). The data were acquired for 20 minutes, beginning 20 minutes after the intravenous administration of 123I- IMP (111MBq). The easy Z-score Imaging System (eZIS) and Voxel Based Stereotactic Extraction Estimation (vbSEE) were used in this study for the quantitative assessment of brain SPECT images. More than 20% decrease in the extent % comparison to the control subjects was used to assess the hypoperfusion in the vbSEE analysis. To determine the frequent hypoperfusion regions in the vbSEE analysis, 80 hemispheres of 40 patients with probable AD (29 female, 11 male, age range 52-82) were analyzed. Nine regions were selected as the frequent hypoperfusion regions including angular gyrus, supramarginal gyrus, inferior parietal lobule, precuneus, middle temporal gyrus, superior parietal lobule, superior temporal gyrus, cingulated gyrus. Among 82 MCI patients (male 21, female 61), 36 patients showed abnormal SPECT (A group) and 46 patients showed normal SPECT (N group). The age and MMSE were not significantly different between the groups. Progression from MCI to AD was observed for the period of 1-5 years. Among 61 patients observed for one year, 17 patients progressed from MCI to AD, including 6 patients in N group (35.3%) and 11 patients in A group (64.7%). The Logrank test demonstrated a significant difference in survival curve between the group A and N (P value=0.00842; p<0.01). The eZIS and vbSEE analysis of SPECT imaging at the initial hospital visit in MCI patients is a useful tool for predicting the progression to AD in the near future.